TLC5940 PWM Driver to control Electronic Speed Controllers

[delic]

I am a bit of a newbie. I am trying to design a quadcopter. I am stuck on how to communicate with the electronic speed controllers, ESC, for brushless outrunner motors. The ESC take a hybrid PWM signal where the pulse width defines the throttle (1ms = zero throttle and 2ms = full throttle).

As the raspberry pi is a little weak in the PWM department I have a bit of a problem. I thought the Texas Insturments TLC5940 PWM driver would help. Even if the TLC5940 would work I still don't know where to get the clock signal for it. Any comments or advice? Can the TLC5940 be used for this?

The ESC would be somthing like this: http://www.hobbyking.com/hobbyking/stor ... oller.html

[delic]

OK i just saw this thread, http://www.raspberrypi.org/phpBB3/viewt ... 37&t=35746
which is the same project. I found info on this adafruit pwm driver with an internal clock
http://www.adafruit.com/products/815#Description

This looks perfect to me. Would it work?

[joan]

The I2C board should be much easier to use. It should work, Extra weight, and I2C transactions are scheduled so another source of jitter at the refresh rates a quadcopter presumably needs.

Perhaps you could compare that solution with one using the Pi's DMA to time the servo pulses.